Is it possible to use Google apps scripts deployed as a web app to integrate into the Google Drive UI?
i.e. opening files similar to: https://developers.google.com/drive/about-sdk#create_and_open_files_directly_from_the_drive_ui
But using Google scripts: https://developers.google.com/apps-script/
Scripts do have access to a drive api, but I'm unsure if they have the capability to integrate into the Drive UI?
Yes. You can create a script, deploy it as a web app and call it from the Drive UI as shown in the link you provide. Your script is passed parameter from the Drive UI (including for example, the folder currently selected) and you work from there... I use this mechanism to work with a folder structure representing client activity. Selecting a client folder, I can choose to open with my script or the usual Drive options. My script checks the parameters passed by drive and responds with an appropriate user interface for the next step.
